Separable attachment-plug.



1,.1 79,728. Patented Apr. 18, 1916.

e. P. KN'APP.

SEPARABLE ATTACHMENT PLUG.

APPLICATION FILED JAN. 11. 1915.

INVE/V TOR WIQW WITNESSES:

'A ITOR/VEY GEORGE P. KNAPP, OF BRIDGEPORT, CONNECTICUT, AS SIGNOR TO HARVEY HUl BBE'LL, I INCORPORATED, OF BRIDGEPORT, CONNECTICUT, A CORPORATION OF GONNEGTICUT.

SEPARABLE ATTACHMENT-PLUG.

Specification of Letters Patent.

Patented Apr. 18, 1916.

Application as January 11, 1915. Serial No. 1,500.

To all whom it may concern Be it known that I, GEORGE P. KNAPP, a citizen of the United States, residing at Bridgeport, county of Fairfield, State of Connecticut, have invented an- Improvement in Separable Attachment-Plugs, of which the following is a specification.

This invention has for its object to provide a portable separable attachment plug especially adapted for use in connection with electric implements, a's chafing dishes, sad irons, &c., or wherever a light is used in connection with a machine or mechanism and there is danger of metal parts likely to be handled by the operator becoming charged with the current owing to a crossing of wires, short circuiting or any mishap likely to happen in connection with electrical wiring, which shall entirely do away with this danger by providing the cap with a supplemental knife blade contact and the base with a corresponding supplemental pair of contact plates which are connected with a binding screw :1 ground wire.

In the accompanying drawing forming a part of this specification, Figure 1 is a perspective view illustrating the use of my novel plug in connection with a. chafing dish; Fig. 2 an elevation of the base and end block assembled; Fig. 3 a bottom plan view of the base; Fig. 4 an elevation of the cap detached; Fig. 5 a section on the line 5-5 in Figs. 2 and 3 looking in the direction of the arrows; Fig. 6 a section on the line 66 in Fig. 3, looking in the direction of the arrows, and Fig. 7 is a View of the supplemental contact plates. and the binding screw.

10 denotes the base and 11 the end block, both made of insulating material, 12 the screw shell and 13 the cap. A three-wire cable leads from the cap to the implement, machine or mechanism where the current is used. Two of the wires are connected respectively to knife blade contacts 14, and the third wire is connected within the cap with a supplemental knife blade contact 15. The base is provided with two chambers 16 having contracted passages 17 leading thereto through the bottom. In each of the chambers there is a pair of contact plates 18 which are adapted to be engaged by knife blade contacts 14 when they are pressed in through the passages. One pair of these for the attachment of contact plates is electrically connected With the screw shell, see Fig. 6, the other pair belng electrically connected with the center contact 19, see Fig. 5. The base is also provided with a chamber 20 having a contracted passage 17 leading thereto through the bottom. In this chamber there is apair of contact plates 21 which are adapted to be engaged by supplemental knife blade contact 15 when it is pressed in through the correand in order to simplify the engagement of the cap with the base, that is to assist in ahmng knife blade. contacts 14 and 15 with the correspondmg passages, I preferably make supplemental knife blade contact 15 slightly longer than knife blade contacts 14.

I also preferably .use substantially the arrangement of knife blade contacts and the corresponding passages illustrated in Figs. 3 and 4.

Contact plates 21 are secured to a plate 22 which extends outward through a recess 23 in the base and is provided with an exterior binding screw 24 to which a ground wire 25 may be attached, as in Fig. 1. The wire in the cable which is connected with supplemental I knife blade contact 15 and which for convenience I will'indicate specifically by 26, leads out from the cable preferably at the point of attachment of the cable to the implement, machine or mechanism, see Fig. 1, and is attached to some portion of the implement, machine or mechanism that is likely to become charged with thecurrent.

Having thus described my invention I claim:

A portable separable attachment plug comprising a plug base having chambers leading in from one end and provided with contracted entrance passages, said base being provided with a center contact, and an end block provided with a shell contact, contact members in independent chambers of said base and connected with the center contact and shell contact respectively, a

ound contact plate attached to said base and leading from one of said chambers to 5 the exterior of the base, said plate having an exterior bindingscrew, a ground contact 10- cated within an independent chamber of said base and connected with said contact plate, and a cap having contact blades and a 10 separate ground contact blade shaped to en- GEORGE P. KNA

Witnesses: H. W. MEADE, E. M. Convex.- 

